KY-556 is a promising, orally-active pro-drug of disodium cromoglycate (DSCG) effective against allergic diseases.

N-556, administered orally at a dosage of 100 mg/kg, has been shown to extend survival times in rats experiencing systemic anaphylaxis and to significantly reduce airway resistance in rat models of experimental asthma. Furthermore, N-556 demonstrated a dose-dependent inhibition of 48-hour homologous passive cutaneous anaphylaxis (PCA) in rats, with effects persisting longer than those observed with Disodium cromoglycate (DSCG) administered intravenously. The compound's oral anti-allergic properties were further confirmed through a regimen of 20 and 100 mg/kg daily for 20 days, which notably suppressed histamine release from lung fragments of actively sensitized rats.